The present invention generally relates to the reduction of sonar dome radiated noise and more particularly to absorbing flow-induced and hull transmitted vibrations that normally excite a ship's keel mounted sonar dome.
One of the most popular prior methods of reducing the vibration in sonar dome windows comprised the placing of sand in the bottom of the dome. The use of sand has been found, however, to be only partially effective in reducing the vibration of the sonar dome window. Another prior system for damping acoustic enclosures covered a submarine signal device with a synthetic rubberlike material. The inner portion of the covering was cellular. The use of a cellular covering has the drawback of damping the desired tramsmitted and received acoustics signals because of the air filled cells.
Other problems encountered in the past related to the use of antifouling paints. Paints applied to the exterior surface of steel sonar domes had a short life when exposed to the underwater elements and sonar transmissions, and in addition often created noise problems.